Transjugular intrahepatic portosystemic shunt: Accuracy of helical CT angiography in the detection of shunt abnormalities

PURPOSE: To determine the sensitivity, specificity and accuracy of helical computed tomographic (CT) angiography in the detection of transjugular intr ahepatic portosystemic shunt (TIPS) stenoses or occlusions. MATERIALS AND METHODS: Thirty-seven patients underwent 50 helical CT angiog raphic examinations and, within 2 weeks of each examination, portography wi th measurement of the portosystemic pressure gradient. Helical CT angiogram s were independently interpreted by three radiologists who were blinded to the results of portography. Results of helical CT angiography and portograp hy were compared. Sensitivity and specificity of helical CT angiography wer e separately calculated for the demonstration of morphologic abnormalities and the determination of their hemodynamic significance. RESULTS: Of the 50 portograms, 31 (62%) demonstrated morphologic TIPS abnor malities, 24 (77%) with and seven (23%) without elevated portosystemic pres sure gradients. Helical CT angiograms correctly demonstrated 30 (97%) of th e 31 morphologic abnormalities and allowed correct diagnosis of 22 (92%) of the 24 hemodynamically significant abnormalities. Nineteen (38%) portogram s were normal; helical CT angiograms correctly demonstrated the absence of a abnormality in 17 (90%) of these cases. Sensitivity and specificity of he lical CT angiography for all morphologic abnormalities were 97% and 89%, re spectively, and, for hemodynamically significant abnormalities, 92% and 77% . CONCLUSION: Helical CT angiography holds promise as a screening modality fo r the detection of TIPS stenoses or occlusions.